GB343129A - Improvements in or relating to means for producing super- or sub-normal pressure in a fluid system - Google Patents

Abstract

343,129. Fluid - pressure brakes; aeroplane control mechanism. INDIARUBBER, GUTTA PERCHA & TELEGRAPH WORKS CO., Ltd., 106, Cannon Street, and AVERY, W. L., of India- Rubber, Gutta Percha & Telegraph Works, Silvertown, both in London. Nov. 11, 1929. No. 34333. [Class 103 (i).] In brake operating means for producing supernormal or sub-normal pressure in a fluid system for operating a vehicle or aeroplane brake or brakes and of the type in which relative movement of two members, such as a cylinder and piston, increases or reduces the volume of a fluid-containing chamber so as respectively to suck fluid into or expel fluid from the chamber to the brakes, a pivoted operating-lever is operatively connected by a cam-slot with one of the relatively movable members so that when the lever is moved to reduce the volume of the chamber the pivot of the lever and the member to which the latter is connected by the cam-slot are caused to approach one another. In the construction shown in the Figure a cylinder 10, containing a piston 13 having a long skirt, is fixed by a saddle 11 to a member 12 which may be a frame member of a vehicle or the rudderbar of an aeroplane. The valve arrangement for regulating the supply of fluid into the cylinder is the same as that described in Specification 340,222, the valve being contained in one end of the cylinder and so connected with the piston that it is open only when the volume of the cylinder is a maximum. The piston 13 is moved against the action of tension springs 19 by a pedal 18 formed on a pair of bellcrank operating-levers 15 pivoting on an axle 16 fixed to the cylinder and each having a cam-slot 17 engaging a pin 14 each end of which projects through the piston-skirt 13 and through a slot in the cylinder wall parallel with the cylinder axis. The shape of the cam-slots 17 is such that the leverage of the levers 15 on the piston increases as the piston moves forwardly in the cylinder. The pedal 18 may be replaced by a hand-lever, in which case triangular apertures may replace the cam-slots 17, or other means, such as a hinged joint in the handlever, may prevent the latter from effecting retraction of the piston. Further, each operating lever 15 may be pivoted in the neighbourhood of its angle about the pin 14 and have a cam-slot at the end of one of its arms to engage a fixed abutment corresponding to the axle 16.